A cobporation of



E. A. W. JEFFERIES. ENGINE FOR LOW TEMPERATURE EXPANSlON.

APPLICATION FILED NOV. 16, l9l8.

Reissued Feb. 25, 1919.

' I Invenfiov STATES. PATENT ormcn.

y mamas A. w. surname, or woncns'rnn, MASSACHUSETTS, ASSIGNOR To JEFFERIES- ,NonToN conPonATIoN', or woncns'rnn, MASSACHUSETTS, A conronA IoN or w To all may concern:

' cBe-it known'gth'at I, EBENEZER A. W.

-Jnrrnnms,=. a citizen of the United States,

residingathWorcester, in the county of Worcester and. Commonwealth of Massachusettsyhave invented a new and useful Imfl pr ovemen't in Engines for Low-Temperature-Expansion, of which the following, to- -gether with theaccompanying drawings, is

a specification.

--The present invention relates to improvementswin enginesused to expand gases to extremely low temperatures, as, for instance, "enginesofQ the class known as cold expansion engines which are employed in the liquefaction of air and other gases My invention is particularly adapted for use in connection with a piston equipped cylinder in which compressed air or other gas, at a low temperature, is still further reduced in temperature, for refrigeration purposes, by expansion, and at the same time is made to expend its energy in producing useful W01 during the admission of the relatively warm compressed gas to the cylinder; upon expansion of the gas, accompanied by a drop in temperature, this heat absorbed by the cylinder walls is given up-to the expanding gas,

-- with the result that the theoretical drop in temperature is not attained. With the use of internal metallic surfaces therefore, as

in all engines of this class now in use, the above described rapid interchanges ofheat between the gas and the metal, involving the alternate absorption and rejection of large quantities of heat by said metal, seriously impair the efliciency of such engines. That is to say, the great amount of heat stored in the metal at each influx of relatively warm gas to the cylinder has the effect of greatly diminishing thenatural drop in tem- ENGINE FOB LOW-TEMPERATURE EXPANSION.

perature duegto the expansion of said gas, thus defeating, to a considerable extent, the object sought to be attained. It is to be understood that the action above described, which is here sought to be remedied, is wholly an internal action, applying only to the rapid changes of temperature'occurring within the cylinder; such changes have no relation to the problem of insulating the cylinder walls from external atmospheric heat, which, of course, can be accomplished -in theordinary way by exterior insulating material, to prevent the passage of heat through said walls.

-The principal object of the present invention is to provide, in engines of the class specified, a suitable interior covering for the Specification of Reissued Letters Patent. Rei sued F b 25 1919.

origiiaiip ucation Med December 1, 1915, Serial No. 64,429. RcnewedIanuary 1a, 1913, Serial No. 1,264,871, dated April 30, 1918. Application for reissue filed November 16, 1918.

metallic inclosing surfaces which would otherwise be in contact with the gas during its expansion, said covering or lining being composed of a material whose capacity for quickly absorbing or rejecting heat is extremely small, as compared to metals. By the provision of such a lining, the losses due to the rapid alternate-absorption and rejection ofheat by the surfaces incontact with the gas are greatly reduced, since the amount of heat so absorbed and rejected will be very small as compared to the amount absorbed and rejected by metallic cylinder walls. It is well known that in ordinary expansion cylinders operating at very low temperatures, that is, temperatures below minus two hundred degrees Fahrenheit, the drop in temperature. due to expansion seldom attains more than forty per cent. of the natural orcalculated range which should be obtained under perfectly isentropic condi-' tions. On the other hand, in anengine having its gas contacting surfacesequipped with a covering in accordance with my in vention, the actual drop in temperature exceeds, in practice, eighty per cent. of the theoretical temperature drop; this action not only increases the efiiciency of the engine, but results in other valuable advantages in that it permits the use of lower pressures to obtain the same degrees of cold, thereby greatly simplifying the construction and operation of such refrigerating machinery and other apparatus for the liquefaction of fluids which are gaseous in their free states.

In the accompanying drawings 1 have represented myinvention asapplied toa'piston equipped cylinder adapted to be used in connection vwith my invention.

Fig. 2 is a transverse sectional view on the plane of the broken l1ne 22, Fig. 1. Similar reference charactersrefer to sim lar parts in the difi'erentfigures.

Referring to the drawings, 1 denotes, as a whole, a cylinder designed to receive and exhaust, successively, charges of compressed air, or othergas, atthe verylow temperatures prevaillng 1n refrigeration and liquefaction systems. A piston 2 within the'cyl inder 1 is operatively connected in the usual manner with any suitable mechanism, not shown, to which. the energy imparted to the piston is transferred.

, The cylinder 1 has an inlet port3, through which the charge of compressed, air, or other gas, at low temperature, is admitted, when the piston 2 is atthe extreme endof its inward movement.

to expand against the piston to force the latter outwardly, thereby reducingthetemperature of the 'gasand utilizing itsexpansive. energy to perform useful work. When the limit, of expansion isvreached, the gas is ex hausted through the outlet port t and, being at a lower temperature than its admissiontemperature, is available for refrigeration purposes, in the usual manner.

According to my invention, the cylinder 1 consists of a metal shell 5, having an inner lining 6 of a specially constructed material, the essential characteristic of which is its incapacity for rapidly absorbing or reje'cting substantial quantities of heat. The lining which I employ, and which constitutes the essential featureof the/present invention, consists'principally of-ffibrous material, such as ipaper,wood fiber, ,or asbestos fiber,suitably. compounded with 'a strong binder, such .as hakelite, and, if desired, with a small amount of graphite,and then molded into rings 7, under high pressure, and with the application of sufficientheat to set the binder.

I may make such annuli, made of ordinary manila drawing paper, upon a hollow mandrel, whose outer diameter is slightly less than the diameter of the piston 2, Before these annuli are assembled on the mandrel, they are soaked with a binder, for exampleliquid bakelite, and one surface may be sprinkled with graphite. The hollow mandrel is then heate by putting its interior spacemnder steam pressure, and the assembled annuli The The compressed air or sure under the influence ofheat. other gas Wltlllll'the cylinder is then allowed lining as described above by assembling large numbers of thin are pressed down upon'eachcther with great force, either in a hydraulic press or by forcing metal rings on the ends of the mandrel toward each other with a series of bolts. eat pressure forces out the superfluous bake ite so that none vof it remains except a binding film between each layer. of paper.

The heat'and' pressure is maintainedior at least twenty-four hours, at the end of which;

time the materials, namely paper, graphite and binder, have become incorporated into a solid The steam is exhausted from the mandrel, which cools and allows the mass, in the form of a ring, to be Withdrawn easily The ring so formed consists principallof compressedpaper fiber, which is easi y turned and bored in a lathe and then presents a smooth, dense blacksurface. This surfacehas a very low capacity for quickly absorbing or I rejecting heat, .is I practically self lubricating', and has the peculiar'property of becoming stronger and more tenacious when subjectedto extreme cold, aprop: erty not possessed by compound substances consisting principally of graphite, or those which have not been formed by great pres- Such rings may be made of any predetermined thickness andforcedinto the metal,

shell 1 to line. the same from end to end.

While I have described one method of making the rings 7-u'sed for lining' the'metal shell, it 'isto be understood that I am not limited to theabovegor any other method of making the lining; obviously, the purposes ofmy invention are-attained by such alming made inany desired manner, and composed principally of fiber, and a suitable binder,

with-or without graphite, the substancesbeing compounded under high pressure and with the prolonged application of sufiicient heat.

provided also with a similar fibrous plate or The head 8 of thecylinder is preferably.

too

manner and having the peculiar properties i above described, its constituent substances being compounded under pressure and with the application ,of heat. piston or'plunger '2 is similarly-faced with a fibrous plate. or covering 10, attached thereto in anysuit'able manner,v made in. substantially the same way, and if desired, the pe- The head of the-- riphery of the piston 2 may havean external 9 covering 11 of the same properties, although thelatter isnot essential, since the lining 6 and plates 9 and 10,'furnish under all Cll: cumstances surfaces of requisite incapacity" for rapid heat absorption or rejection which completely surround the gases admitted to the engine.

I am aware thatlinings for cylinders have previously been suggested, composed princi-.

pally of graphite, in order toavoid the use i of ordinary unctuous lubricants, and especially designed to be used with motive fluids which destroy such lubricants, and I am also aware that it has been roposed to mold such raphite into a suitab e mass by compoundmg it with fiber or the like. Therefore, I make no claim viously, is wholly unsuited for the particular use described above, as graphite is a substance having considerable capacity for rapidly absorbing heat and having small cohesive strength. My invention resides primarily in the discovery that a lining composed principally of fiber, compounded with a suitable binder preferably under high pressure and with the prolonged ap lication of suflicient heat, with or without t e addition of gra hite, has its strengthand permanence of orm, and also its tenacity and durability greatlyincreased atthe extremely low temperatures to which it is subjected in the particular use described above, and it is this property which is essential to the purposesof my invention. Any lining which consists principally of graphite, or which is compounded in the absence of great ressure, accompanied by heat, or in whic an unsuitable binder, such as water with a small percentage of fiber, is employed, does not have these properties, and does not moreover attain to them, even under the influence of intense cold, in'such degree as to render the substance suitable for the purposes which I have described.

Obviously, as I have stated, thegraphite,

which may or may not be used in the compound, as desired, is in no way contributory to the attainment of my principal object, but is incorporated for the obvious purpose '0 providing as far as possible a self-lubricah ing surface, against which the piston 2 can move with mini-mum friction.

I claim,

1. In a device of the character described, a

cylinder for the expansion of gases at ex- I to such a lining which, o'b-' tallic shell or casing havin a lining of low I capacity! heat, w ereby the interchange of substantial quantities of heat between the gas and the surfaces with which it is in contact during expansion is prevented, said lining increas-- ing in hardness and tenacity when subjected to the extremely low temperatures prevail ing in'said cylinder, and consisting principally offibrous material, compounded'with a small percentage of graphite and a binder, by the application of heat and pressure.

3. In a device of the character described, a cylinder for the expansion of compressed fluids which are gaseous in their free state and which have been previously cooled, for

the production of extreme 'cold, comprising a metallic shell orcasing having a lining of low capacity for quickly absorbing or rejecting heat, whereby theabs'orption of sub stantial quantities of heat by said shell from the incoming compressed fluid is prevented, said lining consisting principally of fibrous material compounded with a binder.

11)ated this thirteenth dayof November, 19 8.

EBENEZ'ER A, W. JEF-FERIES.

Witnesses NELLIE WHALEN, PENELOPE COMBERBAGH.

for quickly absor ing or re ecting 

